A PET system is conventionally made of tens to about a hundred detector modules with different timing properties. Conventionally, detector modules are randomly arranged within a PET scanner. For example, for a PET detector having a plurality of detector modules arranged to form the detector ring, the detector modules are typically randomly arranged within the detector ring.
For a time-of-flight (TOF) PET scanner, this randomness usually results in a non-uniform timing resolution in the PET FOV and in the image plane. When modeled appropriately, this non-uniformity makes image reconstruction more complicated, and when not addressed, it deteriorates the image quality.